Such a hydraulic overpressure valve is usually used to limit a hydraulic pressure in a hydraulic machine or a hydraulic system. When the hydraulic pressure increases to exceed a predetermined threshold value the cone element is loaded by the pressure against the force of the force generating means. When the force produced by the hydraulic pressure exceeds the force produced by the force generating means the cone element is moved away from the valve seat and the cone opens a passage so that hydraulic fluid can escape and the pressure in the system decreases. A pressure reducing valve operates in a similar manner. Therefore, the term overpressure valve incorporates a pressure reducing valve as well for this description. Such an overpressure valve has a tendency to be noisy. This is a problem in particular in hydraulic machines and hydraulic systems which are operated near a human operator, for example in a vehicle equipped with a hydraulic steering unit in which such an overpressure valve is built in.